What is the load algorithm?
Jul 4, 2006, 10:33 AM
#16
Originally Posted by l2r99gst
I finally made a few logs today and wanted to try to take a stab at the load formula. I know from my DSMLink experience that it is mainly based off of mass airflow/revolution, along with a few other variables that can change it slightly.
So, looking at my Evoscan logs with the logreader, I came up with this equation which seems to work pretty decently for my car. Maybe a few of you can test it out and see what you come up with:
Load = Maf Hz/ Engine RPM * some variable(s)
For my car I used the "some variable(s)" as a constant of 852, based on a few quick calculations.
So, for example in one of my logs, I was at 1308Hz at 4656 RPM (right at the end of a spoolup after going WOT in 2nd), and my EvoScan log showed timing as 2*.
So, 1308/4656*852=239 So, looking at the 240 load column in my stock map at 4500RPM, the timing value is 2. So that checks out.
Using one more data point: A different run at the top of third I had 1585Hz at 6781 RPM, and the log showed 17* timing.
1585/6781*852=199 So, in the 200 load column in my stock map at 6500, it is 15* timing and at 7000 it is 18* timing. So, 17* checks out there, too.
Obviously, this isn't an exact forumula since I used a constant where I know there are variables, but I think this may help a few people out to get an idea of what there load number is. I know someone already posted how to find what load column you are in, but if this load forumla checks out and you find a constant that seems to work on your setup, you can use the forumla to calculate what load column you are in when you are knocking and how much timing is being pulled as a result.
Eric
So, looking at my Evoscan logs with the logreader, I came up with this equation which seems to work pretty decently for my car. Maybe a few of you can test it out and see what you come up with:
Load = Maf Hz/ Engine RPM * some variable(s)
For my car I used the "some variable(s)" as a constant of 852, based on a few quick calculations.
So, for example in one of my logs, I was at 1308Hz at 4656 RPM (right at the end of a spoolup after going WOT in 2nd), and my EvoScan log showed timing as 2*.
So, 1308/4656*852=239 So, looking at the 240 load column in my stock map at 4500RPM, the timing value is 2. So that checks out.
Using one more data point: A different run at the top of third I had 1585Hz at 6781 RPM, and the log showed 17* timing.
1585/6781*852=199 So, in the 200 load column in my stock map at 6500, it is 15* timing and at 7000 it is 18* timing. So, 17* checks out there, too.
Obviously, this isn't an exact forumula since I used a constant where I know there are variables, but I think this may help a few people out to get an idea of what there load number is. I know someone already posted how to find what load column you are in, but if this load forumla checks out and you find a constant that seems to work on your setup, you can use the forumla to calculate what load column you are in when you are knocking and how much timing is being pulled as a result.
Eric
Jul 4, 2006, 11:09 AM
#17
Originally Posted by chmodlf
Bravo. Just curious are you running an aftermarket intake or stock airbox?
Eric
Jul 4, 2006, 11:14 AM
#18
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Originally Posted by l2r99gst
Right now, my car is basically stock....just a 3" TBE. Cams are going in when they arrive and then the tuning begins. I'm going to try to keep the stock airbox and just use a high-flow filter. Those numbers were a stock airbox with a stock filter.
Eric
Eric
Last edited by chmodlf; Jul 6, 2006 at 04:52 PM.
Jul 4, 2006, 07:15 PM
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Does anyone have a conversion factor to get lb/min from the MAF Hz?
Also, with all of this logging going on, could someone log airflow/RPM on a stock(ish) 4g63 so we can calculate the VE of the stock setup?
l8r)
Also, with all of this logging going on, could someone log airflow/RPM on a stock(ish) 4g63 so we can calculate the VE of the stock setup?
l8r)
Jul 4, 2006, 07:25 PM
#25
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ok I have been trying to create an excel formula to do this for me on a whole log
howevr lets say the rpm data is in colunm a and maf hz is in column c I write"=(c2/a2)*852" and it gives me a value error. it will not perform the c2/a2 part of the equation.
Anybody have any ideas?
howevr lets say the rpm data is in colunm a and maf hz is in column c I write"=(c2/a2)*852" and it gives me a value error. it will not perform the c2/a2 part of the equation.
Anybody have any ideas?
Jul 4, 2006, 07:27 PM
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Originally Posted by Ludikraut
Does anyone have a conversion factor to get lb/min from the MAF Hz?
Also, with all of this logging going on, could someone log airflow/RPM on a stock(ish) 4g63 so we can calculate the VE of the stock setup?
l8r)
Also, with all of this logging going on, could someone log airflow/RPM on a stock(ish) 4g63 so we can calculate the VE of the stock setup?
l8r)
Jul 4, 2006, 07:28 PM
#27
Originally Posted by andenbre
ok I have been trying to create an excel formula to do this for me on a whole log
howevr lets say the rpm data is in colunm a and maf hz is in column c I write"=(c2/a2)*852" and it gives me a value error. it will not perform the c2/a2 part of the equation.
Anybody have any ideas?
howevr lets say the rpm data is in colunm a and maf hz is in column c I write"=(c2/a2)*852" and it gives me a value error. it will not perform the c2/a2 part of the equation.
Anybody have any ideas?
Jul 4, 2006, 07:32 PM
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this is what I am attempting
ps.... I have tried this formula out by hand on several locations and it seems close on my stock 9
edit I have found the multiplier of 782 to be most accurate on my car
ps.... I have tried this formula out by hand on several locations and it seems close on my stock 9
edit I have found the multiplier of 782 to be most accurate on my car
Last edited by andenbre; Jul 4, 2006 at 08:21 PM.
Jul 5, 2006, 11:01 AM
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This is a quote from Evo4Mad (EvoScan programmer) found on openecu.org:
"Ok this is a calculation that I have found that works, this will do until we work out more about Evo8 Roms. Basically exactly what was suggested above already:
The ecu is doing something similiar to this:
load = Airflow weighted for both temp and pressure = air mass/rev
Load = Air Velocity/Rev * Air temp * barometer (0.00486xBar) * 0.625 (128th bar) / 4"
My .02 (chmodlf):
In my mind it seems that this is a more complete formula because it takes into account more variables than just MAF and RPM.
Even though I have looked high and low and most "definitions" of load are MAF and RPM I highly doubt that it is that simple of an algorithm. But I could be wrong.
"Ok this is a calculation that I have found that works, this will do until we work out more about Evo8 Roms. Basically exactly what was suggested above already:
The ecu is doing something similiar to this:
load = Airflow weighted for both temp and pressure = air mass/rev
Load = Air Velocity/Rev * Air temp * barometer (0.00486xBar) * 0.625 (128th bar) / 4"
My .02 (chmodlf):
In my mind it seems that this is a more complete formula because it takes into account more variables than just MAF and RPM.
Even though I have looked high and low and most "definitions" of load are MAF and RPM I highly doubt that it is that simple of an algorithm. But I could be wrong.